Apparatus for bending tubes



Oct. 16, 1951 R, BROWN APPARATUS FOR BENDING TUBES Filed Feb. 20, 1948 INVENTOR. RALPH BROWN,

47'TORNE).

7 Sheets-Sheet 1 R. BROWN APPARATUS FOR BENDING TUBES Oct. 16, 1951 nil i 7 Sheets-Sheet 2 INVENTOR: RALPH .BRow/v;

Filed Feb. 20, 1948 QKMN ATTORNEY Oct'. 16, 1951 R. BROWN APPARATUS FOR BENDING TUBES 7 Sheets-Sheet 5 Filed Feb. 20, 1948 uvmvrom Rm PH BROWN,

s m% @R HTTORNEK Oct. 16, 1951 R. BROWN APPARATUS FOR BENDING TUBES 7 Sheets-Sheet 4 Filed Feb. 20, 1948 Ram BROWN,

ATTORNEY Oct. 16, 1951 R. BROWN 2,571,416

APPARATUS FOR BENDING TUBES Filed Feb. 20, 1948 7 Sheets-Sheet 5 INVEN TOR: RAL PH BROWN;

flrroRMEx Oct. 16, 1951 R. BROWN 2,571,416

APPARATUS FOR BENDING TUBES Filed Feb. 20, 1948 7 Sheets-Sheet 6 I N VEN TOR. RAL PH BRO w/v;

Oct. 16, 1951 R. BROWN 7 ,416

APPARATUS FOR BENDING TUBES Filed Feb. 20, 1948 7 Sheets-Sheet '7 INVENTOR; R41. PH Bnaw/v;

flTTORA/EK Patented Oct. 16, 1 951 APPARATUS FOR BENDING TUBES Ralph Brown, Fallbrook, Calif., assignor to El ec trical Products Corporation, Los Angeles, Calif., a corporation of California Application February 20, 1948, Serial No. 9,814

13 Claims. (01. 497) This invention relates generally to the art of bending hollow bodies, such as glass, and plastic tubing, and it has especial reference to apparatus for imparting bend to tubular units.

The principal object of the invention is to replace the present methods of manually bending tubes for display and industrial uses, and to provide means in and by which dimensional tubular bodies may be arcuately shaped or formed without variation in the lineal extent thereof, and by which the wall thicknesses of the bodies may be controlled.

So to bend a tube in conformity with the object first related is in the interest of economy and expedition for the essential reason that any elongation representing a diversion from the original involves the necessity for restoration to initial length at the expense of time, labor, and material. It is, therefore, required that the bend length be maintained constant and made to follow any desired lineal path within the tube, and controllably to regulate the application of heat selectively to the outer circumference of the tube in accordance with the are desired.

To control the thickness of the walls at the bend in the tube, in answer to the second objective enumerated above, is essential to insure strength, obtain uniformity in the bent products, give a pleasing appearance to the work; and proof them against easy breakage.

Further objects of the invention, therefore, are to provide a system of heating the tubes in which the heat may be varyingly applied to the tube circumference in the area where the bend is to be made, then bending the tube in an arcuate path around a point of generation that is movable, to maintain the tube at the same length after the bend is made as it was before when measured on a lineal section of the tube, and to proportion the rate of stretch or elongation of the tube on the outside to the rate of compression on the inside of the bend substantially to equalize the thicknesses of the opposing walls.

It has been found in practice that there is a definite relationship between the pivotal center of the bending medium and the position of the bending forms and that the establishment and maintenance of this relationship is controllable to impart to tubing a true are shape and, at the same time, to maintain substantially equal the wall thickness inside and outside of the arc without affecting or producing any change in the original length of the tubing as measured on a selected lineal section of the tubing; and this latter attribute is highly desirable becausethereby the formation of characters may be made from tubing of predetermined lengths. The tube prior to bending is softened to plastic condition by heat and o maintained during the bending process. However, it is imperative for the facile control of the bending that the heat be variably applied to the tube laterally of the center line thereof. By heating the two sides of the tube more intensely than the top and the bottom, the bending of the tube is more satisfactory and produces a substantial equalization between outside elongation and inside contraction.

A still further object of the invention, therefore, is to provide apparatus for bending tubular bodies in which the tube material is heated differentially for effecting the easier and more uniform bending of the tube.

A still further object of the invention is to provide a machine for carrying into effect these objects in which the entire process of heating the tubes, bending them, and releasing them for removal, is automatically controlled.

Other objects will appear from the specification following, in connection with the accompanying drawings, which illustrate a preferred form or embodiment of the invention, but which obviously may be modified in many ways without departing'from the spirit of the invention or the scope of the appended claims.

In the drawings:

Figure 1 is a diagrammatic View illustrating generally the principle of making a constant center-line bend,

Figure 2 is a diagrammatic view, illustrating generally the principle of making a constant outside line bend,

Figure 3 is a diagrammatic illustration of a hand bent tube,

Figure 4 is a fragmentary sectional view illustrating instruments and a method of applying heat to a tube,

Figure 5 is a plan view of a modification of Figure 4,

Figure 6 is a sectional end view of a tube, showing by arrows, one way of heating a tube, as practiced today,

Figure '7 is a side view of a machine for carrying my invention into effect,

' Figure 8 is an enlarged sectional, fragmentary detail illustrating the parts shown within dotted circle on Figure '7,

Figure 9 is a fragmentary section on line 99 of Figure 7, looking in the direction of the arrows,

Figure 10 is a plan view of the machine shown in Figure 7 illustrating the operated position of the bending arm,

Figure 11 is a side elevation of the machine shown in Figure '7, but looking from the opposite side thereof, and showing the bending arm in operated position,

Figure 12 is an enlarged elevational detail of a locking device for a length of tubing,

Figure 13 is a plan view of Figure 12,

Figure 14 is an enlarged perspective, fragmentary detail of a form of device for timing the sequential operation of the allied mechanisms,

Figure 15 is a front elevation of a tube bending machine showing the bending arm in operated position,

Figure 16 is a fragmentary sectional detail of the mechanism for operating the tube bending arm,

Figure 17 is a plan view showing the tube support, bending arm, and mold about which the tube is to be bent and the cooperating mold in withdrawn position for restoring the tube to original form after bending,

Figure 18 is a similar view showing the tube bent against and about the mold and the tube restoring mold in cooperative position, the latter mold being shown in section,

Figure 19 is a similar view showing the mold parts in full line position,

Figure 20 is a similar view showing a modification in the application of a metal ribbon to the tube forming parts for controlling the bend line of a tube; the parts are shown in inoperative or normally open position,

Figure 21 is a similar view showing the parts in operative or closed position, with the tube bent to the mold forms,

Figure 22 is.a fragmentary sectional detail on line 2222 of Figure 21, looking in the direction of the arrows,

Figure 23 is a plan view showing the ribbon control as applied to a glass tube hand mold to govern the length of tube and bend section, the mold being shown in open position with a tube len th in place,

Fi ure 24 is a front view of the control shown in Figure 23,

Figure 25 is a plan view showing the relative parts of Figure 23 in operative position, with a tube b nt to multiple angles or in curves,

Figure 26 is a front view of the form shown in Fig 're 25, and

Figure 27 is a flow diagram showing the fluid lines for controlling the machine in its operations throu-h its various cycles.

Softening of tubes in given areas of their lineal extents and circumferences is a prerequisite for hot bending of tubular bodies; but for control ing the bending, either with or without mech nical a"paratus, it is essential that certain areas of the tube be heated to greater degrees than others. In the pr sent instance, the heating occurs on those areas of the tube which are to become the inside and outside of the bend to be made, and this heating is variable, not only in relation to the too and bottom of the bend area, but also in relation to one side or the other, and hence the heating of the tube on those areas which may become the-inside and outside of a desired bent is differentially accomp ished, by preference, to facilitate bending without affecting the lineal axial extent of the tube.

By way of illustration, and to initially explain the invention, inpart, in Figure 4, the heating of the tube ID on two sides by burners II and I2 is clearly illustrated, the character T denoting the area of heat concentration which occurs through the walls of the tube I 0 and is dissipated at points B--B and CC which, therefore, remain cooler than the sides T. There is a heat loss owing to conduction through the bed or support I3, Figures 1'7 to 20, and for this reason, it is necessary that the disposition. of the burners I I and I2 be such that the heat issuing therefrom be caused to impinge against the sides of the tube I 0 below the longitudinal center thereof. The burners II and I2, therefore, whether yielding heat of radiation or convection, are angled to the degree shown in Figure 4, and in any event, so that the heat is applied below the center of the tube. It may also be desirable for greater efficiency in expediting the bending of tubular bodies to heat one side of the tubing to a greater degree than the other. In that event, the heating differential is produced by burners I I and I2, Figure 5, from which it will be seen that the burner I2 is provided with a wider mouth or outlet than the burner II. In both instances stated, the heating of the tube is a differential one that is always under the control of the operator and this is highly important in preserving strains and stresses during bending as contrasted to a general heating, illustrated in Figure 6, in which tubular strength is destroyed or considerably impaired.

To specifically explain the invention, I refer to Figure 10, wherein a table I 4 is secured to a T- shaped member I5 of a frame, generally indicated at I5. The table I4 is provided centrally thereof with a bed or disc I3, shown in Figures 10, 17-21, preferably of asbestos, which is removable and on which the successive operations of heating and bending are performed. On the under side, this table I 4 is provided with a bearing cup 11, Figures 7 and 15, in which is mounted for rotation one end of a vertical column I8, the other end of which is supported in a bearing I9 suitably mounted in a rigid manner upon a cross member 20 of the frame I6. Onto the column I8 is keyed a pinion 2|, Figure 16, which, with the rack end 22' of a bar 22, is disposed within a housing 23 on the column I8. Between washer 24 and rim 25 of bearing cup II, a bracket 26 is carried on and extends at right angles to the column. The upper and lower surfaces of said bracket 26 (see Figure 7), constitutes guideways for upper and lower rails 21 and 23, respectively, to the outer ends of which is secured an upstanding member 29 having a horizontal surface 30 that is flush with the top surface of the table M. A radially disposed arm 3|, Figures '7 and 17 to 21, is bolted to the surface 30 of the member 29 and lies on the table I4 for operation thereover, as presently explained. To the inner end of said arm 3! is fastened a mold or form section 32 having a curvilinear, cross-sectionally semi-circular groove 33, that is adapted to cooperate with a companion section, later referred to, to form a cross-sectionally circular groove for restoring to shape a tube section deformed by heat. Being complementary to the main forming mold, this form section 32 is adjusted to a position enclosing substantially onehalf of the tube only after the bend has been made. The reciprocal movement of the arm 3! and its mold section 32 is effected by the piston of a fluid pressure motor 34 housed in said bracket 25, the piston being-connected to the upstanding I member 29, and the fluid flow to said motor 34 39 to the valve-means 31 by which the fluid is delivered thereto through a line 31 is through a general control valve system, hereinafter more specifically detailed.

A lever 40, Figure 15, is secured to the column -|8 and carries a radially adjustable support 4| upon which is mounted for movement therewith 4| (see Figure for the arm 42 is adjustably connected with the lever 40, the adjustment being efiected by a screw and a knurled knob 2. By means of the rack and pinion combination, detailed in Figure 16, contained in thehousing 23, and heretofore referred to, the column is actuated 'rotatably to swing the lever 40 and its finger 43 on an arc in accordance with the degree of bend desired in a tube that is positioned at one end against the end of the arm 42 and the inside of the finger 43. 'In the position of the parts indicated in Figure 10, the bending arm 42 has completed a 90 bend and the mold section carrying arm 3| is in'position of cooperation with its companion mold, presently described, to enclose the bent tube and restore it to form by internal air or other fluid pressure. Bracket 26 (see Figure 7) which mounts the arm 3! that carries the mold section 32, is held in fixed position against the one end of a slot 59 in an arcuate member 60, by a spring 6|, Figure 10. This arcuate member 60 is connected with the arm 42 by a set screw 62, and is effort thereof is expended, but the arcuate member 63 may continue its travel relative to the stud 63 to the radial position desired.

The center line of the bar 42 intersects the axis of the column l8 and the inner edge of the finger -43 parallels said line and axis. The purpose of this provision is to render this inner edge adjustable with respect to the axis of the column about which the bar swings, this axis being a fixedone,

.45 the spring 6| to a position where the tension and thereby to alter or vary the relationship of the longitudinal axis of a tube to be bent to the axis of rotation of the bar.

' In Figure 1, the tube line KJ which is the .center line of a length of tube, is maintained as such during the bending except for minor varia- 1 tions which are illustrated at E, F, and G, owing to the fact that the curve generated about the center X is a true are, while the actual path traversed by the center line of the tube, if curved about such line, would be represented by J, E, F, G, and H. In Figure 2, the variance of the point about which the curve in a tube is generated is shown in slightly different application for controlling the outside line bend and in Figure 3, a bend by hand is shown, illustrating a marked disparity between the exterior wall and the invside wall. In controlled bending, to govern the thickness of the inside and outside wall, the center o: the'arc to be formed, is shifted with respect to the axial line of the tube and the axis of movement of the forming or bending finger. Referring now to the finger 43, by which the bending of the tube is accomplished, and particularly to Figures 17 and 18, it will be seen that the axis of the tube 4, as placed against the end of the arm 42 and laterally against the inside of the finger 43, is not coincident with the axis of rotation of the arm 42; The differential between the axis of rotation of the bending arm and the point of generation of the bend in the tube controls the elongation and compression, respectively, of the'o'utside and inside wall, and hence the relative thickness thereof, as well as the lineal extent. of

the tube. I The bar 22, on which the rack 22' is formed or provided, is substantially a piston that is housed in and operable by fluid pressure in a cylinder 44 (see Figure 11), the control of the fluid through line 45 thereto being by a valve device 45' operated to open and closed position by impulses through lines 46 and 46, governed by a. general control valve arrangement,. detailed hereinafter. It will be seen, therefore, that the lever 40 is rotatably operated with the column I8 by the rack 22' of the bar 22 under the influence of fluid pres sure in the cylinder 44, and that the bracket 26 (seeFigure 7) upon which the arm 3| is radially movable to carry the semi-circular mold 32 thereof to operative position, is normally a stationary unit when making bends of not greater than angles. "As will appear later, the. operation of the semi-circular mold 32 is sequential to the bending operation of the finger 43, for the reason that it coacts with the mold about which the bend has been made for the purpose of confining the bend, deformed by bending and heat, when pressure is introduced into the tube, to restore its cylindricity to original form. Asseen in Figures 7, 11 and 15, a clamp 41 is provided on'the member Hi to hold fast the tube 4 to be bent upon the surface of the table I4, and a similar clamp isused to hold the tube against dislocation with respect to the bending finger 43 during the heating and bending operation. A form of clamp for this purpose is shown in Figures 12 and 13, from which it will be seen that the body 48, of the clamp is secured by a bolt or otherwise to the finger 43 and is provided with an upstanding channel portion 49 and with rearwardly extended ears 50 supporting a horizontal pin 5|, 'for anchoring one end of a spring 52, the other end of the spring being connected to a pin 53 in a latch member 54. This latch member 54 has two extensions 55 and 55 in right angular relationship, the latter for engaging and clamping the glass tube 4 to the finger 43 and the former, which is a handle or lever when in operative position, that is,'clamping position, being moved to a position, indicated in Figure 11, from which it will be seen that it is operable 'to'release the tube simultaneously with the removal of the inside mold from the'table and tube, as presently explained. Adverting to Figure 11, a downwardly directed burner 5! is adiustably, supported above the table M to heat the mold section 32 when the arm 3| is in withdrawn position. An upwardly directed burner 58 is also adjustably associated with the table to heat the companion mold, later herein referred to. 1

Referring to Figures '7, 10 and 11, heating means for the bend area of a tube and mold form means are illustrated, these means following each other in the sequence named, and being reciprocated in a vertical direction as and 7 for the purposes now described. In the frame I6, and on a planehigher than the table I4, is a suitably supported transverse member 68, upon which is mounted a carriage 69 that is reciprocably movable thereon by a piston 10 connected to the rear end of the carriage and operably, disposed ina fluid pressure cy1inder1l to which fluid pressure from a suitable source 12 'is admitted from a chamber 13 controlled by valves (not shown) that respond to impulses which are automatically set up in lines 14 and 1 5, as fully explained later. At its forward end,

thecarriage 69 mounts. a cylinder 16 that is pro-' vided with a piston 11 to the end of which is connected a carrier means 18 (Figure 9) for a through line 83, the valves being operated by impulses directed through lines 84 and 85 and the impulses occurring in answer to a control mechanism, presently alluded to. One of the mold sections, to-wit, 19, is provided with a pin 86 which projects therefrom. The lever or han-.

dle of the clamp 41, when in horizontal or clamping position, as shown in Figure 11, ex-

tends over the said pin 86 when the forming finger 43 upon which the clamp is carried, is moved to the position shown in said figure and in Figure 10. When, therefore, the mold sections 19 and are lifted from the bent tube, the pin 86, engaging the lever 55, opens the clamp to release the tube. Referring to Figure 9, it will be seen that the mold sections 19 and 80 are pivotally connected to the bottom of the carrier means 18 to have a limited downward movement to encompass and remove readil from the glass tube when respectively lowered and elevated. For this purpose, the rear of the mold sections 19 and 80 are provided with upper surfaces that decline from the horizontal plane thereof, such surfaces, when the mold sections ,dropupon disengagement with the table I4 and tube .4, contacting and being held parallel to the underside of the carrier means 18 and maintaining the mold sections in open position. Also mounted on said carriage 59, immediately at .the rear of and in alignment with the cylinder 16, is a cylinder 81 that is provided with a piston 88 to which is connected a cross member 89, .Figure 15, having lateral guide bars or rods 90 that extend through suitable guides 9| at the sides of the carriage 69. To'the cross member are adjustably connected burners 92 and 93 which are oppositely disposed and angled relatively to each other, to project the heat therefrom to the sides of and below the lateral center of the tube 4. Fuel is supplied to the burners 92 and 93 through flexible pipes 94 and 95 from a manifold 96. Operation of the piston 88 in the cylinder 81 to lower and lift the burners 92 and 93 is by fluid pressure conducted through a line 91 to a valve'chamber 98, in which valves (not shown) are fluid impulse-actuated through lines and o e r-c amped Ii pos om nfi th tahl I4 and specifically upon that part of the tube ganglia 8 that is to be bent, and hence is disposed the area I3, Figure 1'1, represented by the as bestos insert. The burners 92 and 93 are then moved down toward the plate I3 to straddle the tube 4. A predetermined period of time elapses before the glass is rendered sufliciently plastic for bending. The burners are then lifted back to normally inoperative position, whereupon the carriage is retracted to place the molds 19 and 80 immediately over the heated area of the tube, the molds in the former forward position having been heated by the upwardly directed burner58, Figure 11. Thereupon, the mold sections descend upon the plate I3, straddling the heated tube and encasing the major cylindrical area of the heated tube at the inside of the bend line. The bend of the tube thereupon follows. The rotating finger 43, which is a chordal mem ber, controls the position of the center line of the tube 4 with respect to the radius of the arm 42. If the finger 43 is maintained parallel with and laterally shifted relative to arm 42, constant tube lengths may be caried, as shown in Figures 1, 2 and 3. This provision, of course, would move the center line of the tube to one side or the other of the radius of the arm, which rotates about an unchanging pivot, while the chordal member swings the tube about a center eccentric to said pivot, as shown. The cooperating mold arm 3| is then advanced to theposition shown in Figures 18 and 19, to complete the encasement of the bent, but deformed tube. The mold section 32, the end of the bending chord member 43, and the section 80 of the dual mold as.- sembly, are provided with mutually interengaging notches [M for preventing injury to the tube bend and maintaining the mold at the distance correctly to represent the exterior circumference of the original tube, the restoration to which is accomplished by internal pressure of a fluid. In certain practices of the invention, the notches IOI are not used, the outside edges of mold 32 engaging cold portions of the tube 4. When the tube 4 is positioned upon the table I4, the end of the tube 4 adjacent an end of the radial arm 42 is stoppered by a cork, or other suitable plug I02, Figure 8, and the opposite end is enclosed by a body I03 of rubber or other material that is mounted upon a tubular member I04 provided at one end with a nut I05 for compressing the body I03 against an abutment head I06 surrounding said tubular member I04 and expanding it to seal the tube end. By means of a thrust collar I01 loose on said tubular body member I04, and a levered eccentric I08 pivotally connected to the end of the tubular member I04 and operable against said collar I01, the tubular body I03 is moved relative to the collar to produce an expansion of therubber body to seal the tube. Fluid pressure is supplied to the tube 4 through a pipe I09 that is always in communication with the tubular body I04 which is connected to a line I I0 that taps fluid under pressure from a cylinder III having a valve (not shown) controlled by impulses set up in lines I I2 and H3 by a timing the pipe I09. The supply of pressure to the tube '4 to re-form same occurs after the bend has beejn made and while the mold elements are in position, as shown in Figures 18 and 19.

Thereupon, the mold-carryingarm 3I is withdrawn from the bend of the tube and the bendforming head with the mold sections 19 and 80 lifted from the glass tube to position, preparatory to renewing its part in the cycle of operations. The bending chordal arm 42 now returns to normal starting position, which is that substantially shown in Figure 17, for a 90 bend. Obviously, any lesser bends are capable of being made, the bends shown being illustrative, and likewise any bend of greater degree than 90 may be effected by adjustment of the arcuately slotted member 69, as hereinbefore explained.

Referring now to Figuresand 21, the herein described bending of a glass tube to control the bend line thereof, is shown modified bythe provision of a band I I6 which is set for length while the tube is straight to maintain the length of tube on a definite line, such as a center line. This ribbon or band H6 is anchored at one end to a pin II1 upstanding from the table I4, and at the other end is anchored to a screw II8, upstanding from and connected to the radial arm 42, and is disposed immediately above the tube to be bent and substantially parallel with the lineal extent of the tube. In this instance, the radius arm 42 is under radial tension of a spring II9 to maintain taut the band or ribbon II6 as it winds around a pivot pin I20 on the mold 19, positioned for whatever line tube bend may be desired. The forms illustrated in Figures 20 and 21 are, of course, adaptable for use with the instrumentalities heretofore detailed.

In Figures 23 to 26, I have shown how this band control arrangement may be adapted for use in a standard mold form operated manually. In this instance, the ends I2" I and I22 of the sectional mold I23 are connected by the metal ribbon or band I24 which extends above the glass tube 4 and in contact with bending posts I25 on a mold I26 complementary to the sectional mold I23. When the sectional mold I23 is wrapped around the posts I25, the operator holding the-handles I21 and I28, the tube 4 is wrapped around the complementary mold I26.

Hereinbefore, I have referred to conduits or pipe lines for conveying a fluid under pressure from a source to the various valve chambers 31, 13, 82 and 98, for controlling, in the sequence established, the flow of fluid pressure to the various motors 34, 44', II, 16 and 81, to operate them reciprocably. Since, in the present disclosure, the actuating force is pneumatic, the source of such fluid is shown as produced by a compressor I58, from which the distribution is effected from a conduit I5I to conduit I52 by means of a valve treadle 53, the opening of which initiates and maintains the machine in operation through its various cycles. A conduit 296 is a main line for supplying fluid from the compressor I59 to a plurality of regulators I54, I55, I56, I51, I58 and I59, from which it is sequentially released under a predetermined pressure to all of the valve chambers 31, 45', 13, 82 and 98 and through conduit I68 to the valve chamber III, which controls the delivery of the fluid pressure required to restore the work, to-wit, the tube, to its original cylindrical condition. It will be noted that the main pressure lines 31, 45, I2, 83, 91 and I68 are always charged with fluid, and stem from the respective regulators I54-I59, inelusive, and that the valves (not shown) in the chambers 31, 45', 13, 82, 98 and III, are impulse-actuated to admit fluid pressure to the 10 motors 34, 44, H, 16, 81 periodically alternately to effect reciprocation of the motors. Likewise, impulse actuated valves (not shown) in the chamber III control the supply of fluid pressure from the regulator-connected line I68 to the delivery line leading from the chamber I II to the glass tube; and hence it will be clear that the function of the valve chambers and their complements, is merely to govern the fluid supply to the motors, specified above. The impulse controlis automatically implemented by a form of instrumentation illustrated clearly in Figures '1, 10, 15 and 27, from which it will be seen that two relatively spaced rows I6I and I62 of housings for valves are provided, the stems I63 and I64 (Figure 11) of the valves (not otherwise shown, since they are old in the art and form no part of the present invention) projecting beyond the housings and being disposed opposite each other in the stated spaced relationship, their position as shown, Figure 11, being vertical, though any other position would answer the purpose. The lower row I62 comprises three housings I65, I66 and I18, the housings I65 and I66 being relatively close to each other and the housing I68 being spaced a considerable distance from the housing I66, this distance representing a predetermined interval of time, to-wit, that period required to heat the glass tube to a plastic condition through the medium of the burners 93. The upper row I6I comprises a plurality of aligned housings I61 to I16, inclusive, with their valve stems projecting downwardly. Between the rows, I62 and I63 of said valve housings is a bar I19 (Figures 11 and 15) that is supported and operates on suitable guideways and is connected with a plunger I80, by which it is reciprocated. The plunger I88 is a piston that is contained in a cylinder I8I having a fluid pressure pipe connection I82 (Figure 27), and an impulse-actuated valve (not shown) in a chamber I83 connected with impulse-creating lines I84 and I 85 for governing the admission of fluid pressure through pipe I82 (Figure 27). The bar I19, Figure 11, is provided with an upper pawl I86, and

a lower pawl I81, respectively cooperating with the upper and lower valve stems I63 and I64. The upper pawl I86, Figure 14, pivots in said bar I19 and is held pressed against a vertical wall I89 therein by a spring I99, and one side of the upper end of said pawl I86 is beveled as at I9I, while the rear of the pawl is flat. When the bar I19 is moved in one direction to control the fluid pressure for the consecutive operation of various parts of the machine, the beveled edge I9I of the pawl I86 engages seriatim the projecting valve stems I63 and, being maintained in upright position by the vertical wall I89, depresses or moves the valve stems in regular succession. The lowerpawl I81 pivots in the bottom of said bar I19 and is held against a vertical wall I92 by a spring I93. The lower front end of said pawl I81 is beveled at I94 and operates in relationto the valve stems I64 in precisely the same, but reversed, manner, as the pawl I86.

It will be seen that when the valve I53, which may be a foot valve, is operated, the movement of the machine is initiated in that the plunger I8!) is drawn into its cylinder I8I and carries with it the bar I19, the pawls I86 and I81 of which I81 consecutively engages and operates the valve stems I64 of the housings I65 and I66.

When the pawl I81 has traversed the distance between the housing I66 and engages the valve stem I64 of the housing I18, the flow of pressure fluidis admitted to the opposite end of the cylinder I 8I ,Figure 10, thereby causing thebarll}! to travel in the opposite direction and consecutively move the pawl I86 into operative contact with the valve stems I63 of the housings I61 to I16, inclusive. l

''Assuming that the burners 9 2 have been moved to proximity to the tabletop for heating the glass or other tube, the impulsefor actuating the fluid control valve to lower the burners is created by depressing the valve in the housing I66 through line 99. The heat application continues until the pawl I81-traverses the distance from said housing I66 to the housing I18, the depression of the valve stem I64 of which causes the fluid; to produce a reversal of the travel of bar I19 and hence an engagement of the pawl I86 with the valve stem I63 inthe housing I61. This valve produces in the cylinder or chamber 68 an impulse that opens the valve to admit fluid to the opposite end of the motor81 and thereby lift the burners from the tube; and this action is followed by the retraction of the burners and carriage, as the valve in housing I68 is operated by the pawl I86. The mold-motor 16 is then operated to lower the molds upon the heated glass. The stem I63 of housing I69 is actuated by'the pawl I86, the impulse to the valve chamber 82 being created at one side of the motor 16 through line 84 and at the otherside thereof through line 85, controlled by the valve stem I63 the housing I-.' a I Impulses to the valve chamber 45' to control the movement rotarily of the bending area are set up when the valve stem 163 in housing I16 is depressed, the fluid flow traversing lines 46' and, the latter terminating in housing I16. Impuls'es to the valve 'chamber31 to-control the motor 34 for operating the radialmold are set up when-the valvestem' I63 in housing I1I is depressedjthe flow of fluid 'traversing'lines39 and 36, the latter terminating in housing I14."

"Impulses to the valve chamber II I'to supply air to the'tu-be to restore the cross-sectional area are created when the valve stem I63'in housing I12 is" operated, the flow of fluid occurring through line I13 and-I I2, the latter terminating inhousing" I13, It will be understood that where a line is stated as terminating, the fluid pressure is delivered to'the oppositeside of the motor to return the instrument efiected to normal posi tion, and obviously this 'is attended byanexhaust of the fluid previously used to move the element in the opposite direction. L 1

"I claim:

1. In an apparatus of the character disclosed, the combination of a, table for supporting'a length-of tubing, a pivot member disposed axially' of said table and mounting a radial'arm against the end of which" saidtube is adapted/to abut, a chordal bending arm associated with said radial arm to move over the face of and in contact with said table, means to heat the tubing to plastic condition, mold'means vertically and radially reciprocable to enclose a portion of said tubing, and means to operate said radial arm to cause the chordal member to bend the tubing around one of said mold'means' while in contact with the face of said table.

- 2. In an apparatus of the character disclosed, a plane support for a length of tubing, means to heat the tubing in a portion thereof and laterally below the center thereof to a condition of varying plasticity, a chordal arm lying flat upon the 12 face of said support and engaging a portion of the tubing beyond the heated-area thereof and movable to bend the tubing, said arm having an axialpivot, and means to rotate said arm about said pivot upon the face of said support.

'3. In a tube bending machine, a table for supportinga length of tube to be bent, a pivot below said table, anarm connected to said pivot "and provided with a chordal bending means disposed upon and operable over the face of and in contact with said table, means for differentiallyheating the sides of the tube, mold means on the table, and means to rotate said pivot to swing said chordal bending means over the surface of said table, and bend the tube placed there-against over said mold means, and a mold tocooperate with said mold means afterthe bend is made to enclose the bend of the tube while still pliably hot.

'4. In a tube bending machine, a support for a length of tube, a pivot below said support, a chordal bending means, an arm secured to said pivot;- and adjustably carrying said bending means, means reciprocable relative to said supportto heat the tube laterally and then to remove from the tube, a mold means movable against the heatedtube, means to rotate said pivot to move said chordal bending means and tube about: said mold-means, a mold to cooperate with saidmold means after the bend ismade, and means to move said last named mold radially.

5. In a glass tube'bending machinean annular table for supporting a length of tube, an axial pivot-underneath said table, a radial arm secured to'saidpivot provided with a chordal member extending beyond the end of said arm and lying upon the faceof said table, said radial arm having its end in abutting relationship to saidtube means to heat the tube, pneumatically controlled meansto rotate said pivot to move said chordal member over said table and.- bend said tube, means movable on the surface of said table, and on opposite sides'of the, bend of said tube toenclose the heated area of the tube, and means to supply internal pressure to said tube tocorrect any deformity thereof.

6. Ina tube bending machine, a, support for a piece of tube, a radial arm pivoted to swing on top of said support and provided with an adjustable chordal bending member which extends beyond the end of said arm and against which and to the end of said arm the piece of tube is adapted to be placed, a downwardly directed heating means to reduce the tube at the sides thereof to a plastic condition, a mold means movable relative to the surface of the support to provide a bend are for the tube, means to rotate said radial arm and its chordal member to bend the piece of tube, means complementary to said mold means to enclose the bend of the tube, and means to supply internalpressure to the tube to restore the same to original cross section.

'7. In a tube bending machine, a support for a piece of tube, a radial arm pivoted to swing axially relative to and in contact with the top of said, support and provided with a chordal extension for bending a piece of tube placed thereagainst and against the end ofsaid arm, means to reduce the sides of the tube to a more plastic condition than the top or bottom, means to rotate said arm and its chordal extension to bend the tube so heated and means to enclose the bend of the tube while still heated.

-8. In a tube bending machine, an annular,

plane support for a piece of tube, a chordal member swingable relative to and in contact with the support surface and having an axial pivot, said tube lying in parallel juxtaposition to said chordal member, means so disposed as to heat the opposing sides of the tube below the side center to a plastic condition, while maintaining relatively cool the top and bottom of the tube, means to rotate said axia1 pivot to swing said chordal member and the tube lying thereagainst about a center at variance with said axial pivot mold means operable over the face of the support to enclose the heated bent area of the tube, and means to supply internal pressure to said tube While enclosed by said mold means to restore it to original cross section.

9. In a machine for bending glass tubes, the combination of: an annular table for supporting a length of tube, a chordal member having an axial pivot associated and in engagement with said table, said tube being adapted to lie in parallel juxtaposition to said member, differential heating means for the sides of the tube, means to rotate said axial pivot to move said chordal member and bend the tube lying thereagainst about a" a center eccentric to said axial pivot, mold means operable on and over the face of said table to enclose the bent area of said tube while still heated, and pressure means to restore the tube to original form while enclosed in said mold means.

10. In a machine of the character mentioned, the combination of a support for a straight piece of tube, a chordal member having an axial pivot associated with said table, and extending to near but eccentric of the axial pivot thereof, a means movable to a position to heat said tube to plastic condition, a plurality of mold means, one of said mold means being movable adjacent to the heated area of said tube, means to rotate said axial pivot and move said chordal member to bend the heated tube about said mold means and a center eccentric to said pivot means, means to move the other of said molds against the bend in the tube, and into cooperative relation with said first named mold to enclose the bent tube, and means to restore the cross section of the tube while so enclosed.

11. In a machine for bending glass tubes, the

combination of a table for supporting a length 50 of tube, a radial arm pivoted to swing axially relative to and on top of said table, and provided with a chordal extension for bending a piece of tube placed thereagainst and against the end of said arm, means to heat the sides of said tube, a mold over which said tube is bent, said mold provided with a pin, a stud on said table and a stud on said radial arm, a band of metal connected to said last named studs and disposed above said tube, means to hold said band of metal tensioned, and means to move said radial arms to bend said band about the pin on said mold concurrently with the bending of said tube.

12. In a machine for bending glass tubes, the combination of a table for supporting a length of tube, a radial arm pivoted to swing axially relative to and on the top of said table and provided with a chordal extension for bending a piece of tube placed thereagainst and against the end of said arm, means to heat the sides of said tube, a tensioned band anchored at one end to said table and at the other end to said radial arm and disposed above said tube, a guide mold for said tube having a fixed point, and means to move said radial arms to bend said band about the fixed point concurrently with the bending of said tube.

13. In a tube bending machine, a table for a length of tube, a chordal bending means, an arm mounted to pivot below said table and adjustably carrying said bending means, means to heat the table laterally, a mold means movable against the heated tube, means to move said chordal bending means and tube about said mold means, a mold to cooperate with said mold means after the bend is made, means to move said last named mold radially into and out of engagement with said tube.

RALPH BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,064,039 Shively et al. Dec. 15, 1936 2,265,070 Goode Dec. 2, 1941 2,476,658 Greiner July 19, 1949 

